It is shown that the BaTiO3 ceramics has a tetragonal structure and the split in (002)/(200) peaks near 451(2y) indicates a tetragonal distortion. In contrast, the XRD patterns of the films, especially in (002)/(200) peaks splitting, indicate a pseudocubic phase. This result suggests that the tetragonal phase is more stable than the cubic phase in the thin films [7]. The pseudocubic phase occurs when the grain size decrease sufficiently so that the unit cell becomes less and less tetragonal as a result of the internal strain [5]. The broaden XRD peaks were observed, which manifests the decreased grain size. A core–shell model is used to explain the deformation in BaTiO3 thin films [8]. In this model, a grain has a composite structure consisting of